This invention relates to a tensegrity structure and more particularly to such a structure which is constructed from a number of tensegrity modules.
In his U.S. Pat. No. 3,063,521, Richard Buckminster Fuller introduced the tensile integrity, or tensegrity, construction technique. Tensegrity construction is based on the realization that most building materials are much more efficiently utilized, smaller cross sectional areas can be employed, and the materials can often withstand higher forces, when in tension than when in compression. In tensegrity construction there is a high ratio of tension to compression elements. The tension elements provide continuous lines of tension throughout a structure; whereas there is separation of the compression forces such that the compression members are discontinuous. The compression members in effect float within a sea of tension.
In the above-mentioned Fuller patent, the basic tensegrity element is an octahedron formed of three column-like compression members arranged in a tepee fashion with the ends thereof interconnected by tension wires or cables. The end of each compression member is positioned near the vertex of the octahedron where tension elements intersect, and each tension element runs along an edge of the octahedron. The octahedrons are joined vertex-to-vertex, the compression members thus being in "apparent" continuity. The term apparent continuity is used, for although the continuity in a structural sense is real, because of the resultant tension forces at each intersection of the vertices, the result is discontinuity in respect of functions in compression at that point. The compression members are joined end-to-end but no compressive force is transferred through the intersection.
In a more recent Fuller U.S. Pat. No. 3,354,591, octahedral tensegrity modules are joined face-to-face with compression members of each two interconnecting modules connected at the three vertices of the abutting faces. Each tensegrity module advantageously has a pure tension to pure compression element ratio of four to one. However, with the modules joined face-to-face, the tension elements along the edges of each abutting face become redundant; that is, two tension wires are provided along a single edge where only one is required. If one of those redundant tension elements were eliminated for each edge, the ratio between tension and compression elements is reduced to three to one.
An object of the present invention is to provide tensegrity structure which makes optimum use of each tension element within the structure while keeping a high ratio of tension to compression elements.